Electrically-operated steering lock device

ABSTRACT

An electrically-operated steering lock device which is capable of unlocking the steering shaft even when steering wheel torque is applied to the steering shaft. The electrically-operated steering lock device comprises the lock bolt for locking the steering shaft. The lock bolt is composed of a first lock bolt which is pivotably held on one radial side in a neighborhood of the steering shaft and which has a protruding piece to be engaged on its inner peripheral side with a receiving portion of the steering shaft, and a second lock bolt which is pivotably held on the other radial side in the neighborhood of the steering shaft, which is rotatable to a protrusion position and a retreat position along with the first lock bolt and which has a protruding piece to be engaged on its inner peripheral side with the receiving portion of the steering shaft. The protruding pieces of the two lock bolts are moved each in such a direction as to go away from the engaging surface of the receiving portion of the steering shaft when the engagement is released.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to an electrically-operatedsteering lock device.

[0002] A conventional electrically-operated steering lock device is sodesigned that, for locking of the steering of a vehicle, a lock bolt isprotruded toward a steering shaft by biasing force of a spring so as tobe engaged with a recessed portion of the steering shaft, by which thesteering shaft is locked. Further, an electric motor, which is a lockbolt driving means, is driven into rotation so that the lock boltengaged with the steering shaft is withdrawn from the recessed portion,by which the steering shaft is unlocked.

[0003] Then, with the steering shaft in a locked state, while aso-called steering wheel torque is applied to the steering shaft, thelock bolt is burdened with a load in the rotational direction of thesteering shaft. As a result of this, the engagement between the lockbolt and the recessed portion of the steering shaft becomes tighter,making it harder for the lock bolt to come out of the recessed portion.

[0004] Therefore, in such a state, even if the electric motor isrotationally driven, it can occur that the lock bolt will not come outof the recessed portion on account of the load. In this case, after thesteering wheel is moved to some extent to release the steering wheeltorque, the electric motor is actuated again, thus allowing the lockbolt to come out of the recessed portion. However, for making the lockbolt to come out of the recessed portion, as shown above, there is atroublesome requirement that the electric motor is started up twice,which can be predicted to lead to a reduction in the serve life of theelectric motor.

[0005] As a countermeasure for this, an electrically-operated steeringlock device described in Japanese Patent No. 3174008 (hereinafter,referred to as “Patent Reference 1”) is provided with a locking memberfor locking a steering shaft, an unlocking spring member for biasing thelocking member toward an unlocking position, and a drive member whichactuates the locking member toward the unlocking position via theunlocking spring member and which is actuated by an electric motor. In astate that a steering wheel torque is acting on the locking member, adisplacement of the drive member by the electric motor is absorbed bythe unlocking spring member, so that spring force is accumulated. Then,when the steering wheel torque is released, the locking member is movedto the unlocking position by the accumulated force of the unlockingspring member, by which the steering shaft is unlocked. As a result ofthis, it is made possible to unlock the steering shaft without startingup the electric motor twice.

[0006] However, in this Patent Reference 1, there has been a problemthat the operator, in order to release the steering wheel torque, isrequired to operate the steering shaft each time, which is troublesome.

[0007] Further, in this Patent Reference 1, the locking member isprotruded toward the steering shaft by the biasing force of the springmember so as to be engaged with a locking recess of the steering shaft,by which the locking the steering shaft is locked.

[0008] However, with this structure, there is a possibility that thesteering shaft might illicitly be unlocked by operating the lockingmember against the biasing force of the spring member by magnet or thelike with an aim of theft.

[0009] As a countermeasure for this, it is conceivable that the springmember for biasing the locking member toward the lock position ischanged to one of stronger spring force. However, in such a case, theelectric motor to be used for actuating the locking member against thebiasing force of the spring member needs to be a large-sized electricmotor of large operating torque. This would lead to a problem that thepower consumption is increased, causing the electrically-operatedsteering lock device to be increased in size.

[0010] As another prior art, on the other hand, whereas the conventionalelectrically-operated steering lock device is so designed generally thata lock bolt which is to be engaged with a steering shaft to lock thesteering shaft is actuated by driving force of a motor or the like tolock or unlock the steering shaft, an electrically-operated steeringlock mechanism described in Japanese Patent Laid-Open Publication No.2002-234419; (hereinafter, referred to as “Patent Reference 2”) is sodesigned that a plate cam for moving a lock pin (equivalent to the lockbolt) is driven by a motor to make a plunger of a solenoid protruded toan engagement recessed portion of the plate cam, thereby restraining therotation of the plate cam, so that the motor is prevented frommalfunctioning due to electrical noise. Further, for the prevention ofmalfunctions of the solenoid due to electrical noise, the power for thesolenoid is interrupted in response to operation of a start-up meansprovided on the vehicle, thereby maintaining the motor in the restrainedstate by the solenoid.

[0011] However, in this Patent Reference 2, there is a possibility thatvibrations of the vehicle due to the running might cause the plunger ofthe solenoid to be moved, making the motor deregulated. Further, whilethe plunger of the solenoid is not protruded to the engagement recessedportion of the plate cam, it can occur that the power for the solenoidmay be interrupted for some reason, putting the motor to an operablestate.

SUMMARY OF THE INVENTION

[0012] Accordingly, in a first aspect of the present invention, whichhas been accomplished in view of the above-described problems of theprior art, a first object of the invention is to provide anelectrically-operated steering lock device which is capable of unlockingthe steering shaft even when steering wheel torque is applied to thesteering shaft and which is improved in anti-theft property.

[0013] Additionally, in a second aspect of the present invention, whichhas been accomplished in view of the above issues of the another priorart, a second object of the invention is to provide anelectrically-operated steering lock device which is prevented frommalfunctions of the motor serving for actuating the lock bolt and thuswhich is of high safety.

[0014] As a solution to the above-described first object, in a firstaspect of the invention, there is provided an electrically-operatedsteering lock device comprising a lock bolt which is movable between aprotrusion position where a steering shaft is locked and a retreatposition where the steering shaft is unlocked, and actuating means foractuating the lock bolt from the protrusion position to the retreatposition, wherein the lock bolt is composed of a first lock bolt whichis pivotably held on one radial side in a neighborhood of the steeringshaft and which has a protruding piece to be engaged on its innerperipheral side with a receiving portion of the steering shaft, and asecond lock bolt which is pivotably held on the other radial side in theneighborhood of the steering shaft, which is rotatable to the protrusionposition and the retreat position along with the first lock bolt andwhich has a protruding piece to be engaged on its inner peripheral sidewith the receiving portion of the steering shaft, and wherein theprotruding pieces of the two lock bolts are moved each in such adirection as to go away from the engaging surface of the receivingportion of the steering shaft when the engagement is released.

[0015] With this constitution, the protruding pieces of the first andsecond lock bolts to be engaged with the receiving portion of thesteering shaft are allowed to come out of the receiving portion whilebeing actuated in each such a direction as to go away from the engagingsurface of the receiving portion of the steering shaft. Therefore, thedegree of engagement between the receiving portion and the protrudingpieces is reduced, so that the protruding pieces can be easily pulledout from the receiving portion. As a result, there can be eliminated amalfunction that the steering shaft cannot be unlocked even with atorque applied to the steering shaft.

[0016] Also, in the electrically-operated steering lock device of thefirst aspect of the invention, it is also possible that each of theprotruding pieces of the two lock bolts has a slope surface provided onits outer peripheral side for avoiding interference with the receivingportion of the steering shaft.

[0017] With this constitution, the protruding pieces of the two lockbolts come to be engaged with the receiving portion of the steeringshaft only on their inner peripheral sides, respectively, while theslope surfaces provided on the outer peripheral sides of the protrudingpieces do not interfere with the receiving portion of the steering shaftwhen the protruding pieces come out of the receiving portion. Therefore,the lock bolts can reliably be actuated from the protrusion position tothe retreat position.

[0018] Further, in the electrically-operated steering lock device of thefirst aspect of the invention, it is also possible that the actuatingmeans comprises a cam member which has a first cam wall surface formaking the first lock bolt rotated from the protrusion position to theretreat position and a second cam wall surface for making the first lockbolt rotated from the retreat position to the protrusion position, and acoupling means for actuating the second lock bolt responsive to anactuation of the first lock bolt along therewith, and wherein the firstlock bolt is held at the protrusion position by the cam member.

[0019] With this constitution, since the lock bolts are actuated to theprotrusion position and the retreat position by the cam member, there isno need for any biasing member for biasing the lock bolts to theprotrusion position or the retreat position. Further, since the lockbolts are held at the protrusion position by the cam member, an attemptto operate the lock bolts by magnet or the like with an aim of theftcould not be achieved. Thus, the anti-theft property can be improved.

[0020] Further, in the electrically-operated steering lock device of thefirst aspect of the invention, it is also possible that each of theprotruding pieces of the two lock bolts has an acceptance surfaceprovided on its inner peripheral side for accepting torque of thesteering shaft in a direction generally vertical to a rotationaldirection of each of the first and second lock bolts.

[0021] With this constitution, even if a steering wheel torque isapplied to the steering shaft, almost no force in the rotationaldirection is exerted to the first and second lock bolts. As a result,the load on the cam member that is in contact with the first lock boltcan be reduced, and the cam member becomes operable with smaller force.

[0022] Furthermore, in the electrically-operated steering lock device ofthe first aspect of the invention, it is also possible that theelectrically-operated steering lock device further comprises a springfor biasing the cam member in a direction toward a lock position, and arotor which has an engagement portion to be brought into contact withone end side of the spring to make the cam member rotated toward thelock position via the spring and which is rotated by drive of a motor tomake the cam member rotated, wherein when the lock bolt is unable to beactuated to the protrusion position, the spring absorbs a move of therotor and biases the cam member toward the lock position.

[0023] With this constitution, the rotor is allowed to rotate to itslock position even when the lock bolts are inhibited from beingprotruded to the lock position, and the lock bolts are automaticallyprotruded by the biasing force of the spring when the lock bolts havebecome protrudable, thus making it possible to lock the steering shaft.Therefore, it is no longer necessary to actuate the motor once again toactuate the rotor. Further, since this spring is provided on the cammember, operating the lock bolts does not cause the spring to beactuated, so that the steering shaft is not unlocked.

[0024] As a solution to the above-described second object, on the otherhand, in a second aspect of the present invention, there is provided anelectrically-operated steering lock device comprising a lock bolt whichis movable between a protrusion position where a steering shaft islocked and a retreat position where the steering shaft is unlocked, andan actuator for actuating the lock bolt and, at least, holding the lockbolt in a retreat position in an inactive state, theelectrically-operated steering lock device further comprising powersupply control means for controlling conduction to the actuator, whereinthe power supply control means, upon receiving a vehicle state signalfrom a vehicle, interrupts the conduction to the actuator.

[0025] With this constitution, it is decided by the vehicle state signalthat the lock bolts are in an unnecessary-to-actuate state. Thus, byinterrupting the power supply for the actuator itself that actuates thelock bolts, malfunctions of the actuator can be prevented, so that thelock bolts can reliably be maintained in the retreat state.

[0026] Also, in the electrically-operated steering lock device of thesecond aspect of the invention, it is also possible that the vehiclestate signal is a signal generated by an operation position of anignition switch for starting up the engine.

[0027] With this constitution, since the power supply for the actuatoris interrupted by the operation position of the ignition switch thatchanges the state of the vehicle by manual operation, the power supplyfor the actuator can be interrupted more reliably.

[0028] Further, in the electrically-operated steering lock device of thesecond aspect of the invention, it is also possible that theelectrically-operated steering lock device further comprises a cammember which is actuated by the actuator so as to be engaged with thelock bolts for actuating the lock bolts, and which, when placed in alock position, holds the lock bolts in the protrusion position.

[0029] With this constitution, since the cam member for holding the lockbolts in the protrusion position is provided, it never occurs that thelock bolts are moved to the retreat position by vibrations due to therunning of the vehicle. Thus, the lock bolts can be maintained in theretreat state more reliably.

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention will be further described with reference tothe accompanying drawings wherein like reference numerals refer to likeparts in the several views, and wherein:

[0031]FIG. 1 is a sectional top view showing an electrically-operatedsteering lock device according to an embodiment of the presentinvention;

[0032]FIG. 2 is a sectional side view showing the electrically-operatedsteering lock device according to the embodiment of the invention;

[0033]FIG. 3 is a sectional front view taken along the line A-A of FIG.1;

[0034]FIG. 4 is a view showing an unlocked state in FIG. 3;

[0035]FIG. 5 is a sectional view showing an example of operation of theelectrically-operated steering lock device according to the embodimentof the invention;

[0036]FIG. 6 is a partly enlarged view of FIG. 3;

[0037]FIG. 7 is a sectional view taken along the line B-B of FIG. 1;

[0038]FIG. 8 is a front view of a first lock bolt of theelectrically-operated steering lock device according to the embodimentof the invention;

[0039]FIG. 9 is a front view of a second lock bolt of theelectrically-operated steering lock device according to the embodimentof the invention;

[0040]FIG. 10A is a front view of a rotor of the electrically-operatedsteering lock device according to the embodiment of the invention;

[0041]FIG. 10B is a side view of the rotor of the electrically-operatedsteering lock device according to the embodiment of the invention;

[0042]FIG. 11A is a front view of a cam member of theelectrically-operated steering lock device according to the embodimentof the invention;

[0043]FIG. 11B is a rear view of the cam member of theelectrically-operated steering lock device according to the embodimentof the invention;

[0044]FIG. 12 is a block diagram of a control circuit section of theelectrically-operated steering lock device according to the embodimentof the invention; and

[0045]FIG. 13 is a view showing an operation knob of a vehicle.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0046]FIGS. 1, 2 and 3 show an electrically-operated steering lockdevice according to first and second aspects of the present invention.This electrically-operated steering lock device is so constructed that afirst lock bolt 1, a second lock bolt 2, a motor 3 which is an actuator,a final reduction gear 4, a rotor 5, a cam member 6 which is anactuating means, a solenoid 7, a printed circuit board 8, and a base 9for fixing the foregoing members are all arranged within a housing 10and housed therein with a cover 11.

[0047] As shown in FIG. 8, the first lock bolt 1 is formed of aplate-shaped body portion 13, where a bearing portion 14 is protrusivelyprovided on one end side of a top surface of the body portion 13 and abearing hole 15 is bored at a tip end portion of the bearing portion 14.On the other end side of the top surface of the body portion 13 isprovided a protruding piece 16 protruding parallel to the bearingportion 14. This protruding piece 16, as shown in FIG. 3, is so designedas to protrude outward from a through hole 11 a of the cover 11 when thefirst lock bolt 1 rotatably held at the bearing hole 15 by the cover 11is rotated in the protruding direction (counterclockwise). Theprotruding piece 16 in the protruded state is engaged with a receivingportion 98 of a steering shaft 97 of the vehicle, thereby locking thesteering shaft 97.

[0048] Also, on one side face of the protruding piece 16 on the bearingportion 14 side is formed an acceptance surface 16 a, which is a surfaceengaged with the receiving portion 98 of the steering shaft 97, as shownin FIG. 6. The engagement position of these acceptance surface 16 a andreceiving portion 98 is so set as to be slightly upward, as viewed inthe figure, of the bearing portion 14 on which the first lock bolt 1 ispivotably held, so that when the protruding piece 16 goes out of thereceiving portion 98, the acceptance surface 16 a of the protrudingpiece 16 moves so as to go slightly away from its confronting surface ofthe receiving portion 98. Meanwhile, on the other side surface of theprotruding piece 16 is provided a slope surface 16 b for avoidinginterference with the receiving portion 98 during the rotation of thefirst lock bolt 1. Further, a coupling-use elongate hole 17 is formed onthe lower side of the protruding piece 16. Furthermore, a contactsurface 18 formed into a generally circular-arc shape, with which alater-described cam member 6 comes into contact, is formed on the lowerend face of the body portion 13. Also, on the front-face side of thefirst lock bolt 1 is provided a convex portion 19 onto which anengagement piece 21 having an engagement protruding portion 22 is to beengaged and fixed.

[0049] As shown in FIG. 9, the second lock bolt 2 is formed into agenerally U-shaped plate-like one, and a bearing portion 26 isprotrusively provided on the right side of the top surface as viewed inthe figure, and further a bearing hole 27 is bored at its tip endportion. On the left side of the top surface of the second lock bolt 2is provided a protruding piece 28 which is protruding parallel to thebearing portion 26. On a lower side of this protruding piece 28 isprovided a coupling convex portion 29 which enters the coupling-useelongate hole 17 of the first lock bolt 1 so as to be engaged therewith,and this coupling convex portion 29 and the coupling-use elongate hole17 constitute a coupling means. This second lock bolt 2, as shown inFIG. 3, is so constructed as to be pivotably held at the bearing hole 27by the cover 11 on one side opposite to the side on which the first lockbolt 1 is located with the steering shaft 97 interposed therebetween.The coupling convex portion 29 of the second lock bolt 2 is to beengaged whit the coupling-use elongate hole 17, by which the second lockbolt 2 is adapted to be interlocked with the first lock bolt 1. Thus, asthe first lock bolt 1 is rotated in the protruding direction, the secondlock bolt 2 is interlocked therewith and rotated together in theprotruding direction, while the protruding piece 28 of the second lockbolt 2 is protruded outward from the through hole 11 a of the cover 11simultaneously with the protruding piece 16 of the first lock bolt 1.The protruding piece 28 in the protruded state is engaged with thereceiving portion 98 of the steering shaft 97 of the vehicle togetherwith the protruding piece 16 of the first lock bolt 1, thereby lockingthe steering shaft 97.

[0050] Also, in the second lock bolt 2, an acceptance surface 28 a,which is a surface to be engaged with the receiving portion 98 of thesteering shaft 97, is formed on one side face of the protruding piece 28facing the bearing portion 26 as shown in FIG. 6. The engagementposition of these acceptance surface 28 a and receiving portion 98 is soset as to be slightly upward, as viewed in the figure, of the bearingportion 27 by which the second lock bolt 2 is pivotably held, so thatwhen the protruding piece 28 goes out of the receiving portion 98, theacceptance surface 28 a moves so as to go slightly away from itsconfronting surface of the receiving portion 98. Meanwhile, on the otherside surface of the protruding piece 28 is provided a slope surface 28 bfor avoiding interference with the receiving portion 98 during therotation of the second lock bolt 2.

[0051] The motor 3, which is connected to a motor drive relay 81 (shownin FIG. 12) via unshown lines laid in the housing 10, is rotated forwardand reverse by the control of the motor drive relay 81 by alater-described control unit 76. This motor 3, as shown in FIGS. 1, 2and 3, rotates the final reduction gear 4 via a rotating mechanism 32.This rotating mechanism 32 is composed of a pinion 33 fitted to a driveshaft 3 a of the motor 3, a large-diameter wheel 34 to be meshed withthis pinion 33, and a coaxial small-diameter wheel 36 integrallyprovided with a rotating shaft 35 of the large-diameter wheel 34. Thesmall-diameter wheel 36 is to be meshed with a segment gear 4 a formedon the outer periphery of the final reduction gear 4. As a result ofthis, as the small-diameter wheel 36 is rotated clockwise as viewed inFIG. 3, the final reduction gear 4 is rotated counterclockwise.Conversely, as the small-diameter wheel 36 is reverse rotatedcounterclockwise as viewed in FIG. 1, the final reduction gear 4 isrotated clockwise.

[0052] The final reduction gear 4 is formed into a generally fan shapewith the segment gear 4 a formed on its outer periphery as shown in FIG.7, and a generally D-shaped coupling hole 40 is formed at a center ofthe final reduction gear 4. This final reduction gear 4 is rotatablyaccommodated in a generally fan-shaped accommodation recessed portion 11b provided in the cover 11, and regulated in its rotational range.

[0053] The rotor 5, as shown in FIGS. 10A and 10B, comprises adisc-shaped base portion 41, and a coupling portion 42 protruding in agenerally D shape in cross section is formed on the rear face side, i.e.final reduction gear 4 side, of the base portion 41. This couplingportion 42 is fitted and coupled to a coupling hole 40 of the finalreduction gear 4, and the rotor 5 is rotated together by the rotation ofthe final reduction gear 4. Also, a shaft insertion hole 43 is providedat the center of the coupling portion 42 so as to extend therethroughand, as shown in FIG. 2, the rotor 5 is rotatably held by a shaft 46which is inserted through the insertion hole 43 and fixed between thebase 9 and a plate 12 for accommodating the final reduction gear 4 inthe accommodation recessed portion 11 b of the cover 11. Further, asshown in FIG. 10A, on the front face side of the base portion 41, areprotrusively provided a locking-use engagement portion 44 and anunlocking-use engagement portion 45, respectively. The locking-useengagement portion 44 is to rotate a later-described cam member 6counterclockwise by engagement with the cam member 6, and theunlocking-use engagement portion 45 is to rotate the cam member 6clockwise by engagement with the cam member 6.

[0054] The cam member 6 is generally fan-shaped in cross section asshown in FIGS. 11A and 11B, and a bearing hole 47 is provided at acentral portion so as to run therethrough and is rotatably held by theshaft 46 inserted through the bearing hole 47. On the outer peripheralside of the bearing hole 47 of its rear face (i.e., rotor 5-side), aspring accommodation recess 48 which is opened at its one end and whichhas a spring receiving surface 48 a formed on the other end is formedalong the outer edge of the circular-arc portion 49. The locking-useengagement portion 44 of the rotor 5 operably enters the inside of thisspring accommodation recess 48, and a spring 54 is accommodated betweenthe locking-side engagement portion 44 and the spring receiving surface48 a in the spring accommodation recess 48. Also, an engagement surface50 with which the unlocking-use engagement portion 45 of the rotor 5 isto be engaged is formed on the side face of the circular-arc portion 49of the cam member 6. Accordingly, referring to FIG. 3, as the rotor 5 isrotated clockwise, the unlocking-use engagement portion 45 is engagedwith the engagement surface 50 of the cam member 6, making the cammember 6 rotated clockwise together. Meanwhile, as the rotor 5 isrotated counterclockwise, the locking-use engagement portion 44 of therotor 5 biases and rotates the cam member 6 counterclockwise via thespring 54.

[0055] Further, the cam member 6 has, on one side face thereof, a firstcam wall surface 51 for rotating the first lock bolt 1 from a protrusionposition to a retreat position by pressing the contact surface 18 of thefirst lock bolt 1 outward (toward a direction away from the steeringshaft 97) by the cam member 6 rotating clockwise in FIG. 3. The cammember 6 also has a second cam wall surface 52 for rotating the firstlock bolt 1 from the retreat position to the protrusion position bypressing the contact surface 18 of the first lock bolt 1 inward (towarda direction approaching the steering shaft 97) by the cam member 6rotating counterclockwise.

[0056] The solenoid 7, which is actuated upon reception of a start-upsignal from the control unit 76, has its plunger 61 moved toward thesolenoid 7 side in its actuated state as shown in FIG. 1, and is fixedon the base 9. At a tip end portion of this plunger 61, is fixed alocking member 62 which is to be engaged with the engagement protrudingportion 22 of the engagement piece 21 of the first lock bolt 1 to blockthe rotation of the first lock bolt 1. Between this locking member 62and the solenoid 7, a spring 63 is provided around the plunger 61, andthe locking member 62 is biased toward the engagement piece 21 by thebiasing force of the spring 63 while the solenoid 7 is not actuated.Then, in the state that the first lock bolt 1 is in the retreatposition, while the solenoid 7 is not actuated, the side wall of thelocking member 62 is engaged with the engagement protruding portion 22of the engagement piece 21 as shown in FIG. 4, thereby preventing thefirst lock bolt 1 from rotating toward the protrusion position (i.e.,counterclockwise). Further, under the locking member 62 of the solenoid7, a move detection portion 64 is provided so as to extend from theunderside thereof.

[0057] Below the solenoid 7, as shown in FIG. 1, is disposed a movedetection switch 66 for detecting the actuation of the plunger 61 of thesolenoid 7, so that a detection portion 67 of the move detection switch66 makes contact with the move detection portion 64 of the lockingmember 62 to detect the actuation of the solenoid 7. This solenoid 7 iscoupled to the control unit 76 by an unshown connecting line to transmitthe actuation of the solenoid 7 to the control unit 76.

[0058]FIG. 12 is a block diagram of a control circuit section 70 forcontrolling the operations of the solenoid 7 and the motor 3 in theelectrically-operated steering lock device of the present invention.This control circuit section 70 is made up of unshown electroniccomponents on the printed circuit board 8. The solenoid 7 controlled bythe control circuit section 70, and the motor drive relay 81 foroperating the motor 3, are connected to a battery via an ACT-use powersupply unit 71, which is a power supply control means, where agrounding-side terminal of the solenoid 7 is connected to the controlunit 76 and a grounding-side terminal of the motor drive relay 81 isconnected to a PGND terminal 80 to be grounded. The ACT-use power supplyunit 71 is connected both to a battery terminal 72, which is connectedto the battery, and to a power supply control terminal 73, which isconnected to an ignition switch 83 for starting up the engine.Furthermore, this ACT-use power supply unit 71 has a switch function ofswitching between supply and interruption of electric power to thesolenoid 7 and the motor drive relay 81 according to an input signalderived from the power supply control terminal 73. Specifically, forexample, within the ACT-use power supply unit 71 is provided atransistor 71 a as a switching element, having an emitter connected tothe battery terminal 72, a base connected to the power supply controlterminal 73, and a collector connected to the solenoid 7 and the motordrive relay 81. Then, when the power supply control terminal 73 isgrounded, power supply to the solenoid 7 and the motor drive relay 81 iseffected. Meanwhile, when the power supply control terminal 73 is notgrounded, power supply to the solenoid 7 and the motor drive relay 81 isinterrupted.

[0059] The ignition switch 83, as shown in FIG. 13, is operated for aplurality of switch operations by rotation of the engine start-upoperation knob 85 provided in the vehicle. As the engine start-upoperation knob 85 is rotated from a LOCK position, where the steeringshaft *97 is locked, to a START position via an ACC position and an ONposition, the engine starts up, ready for running. Then, with theoperation knob 85 in the LOCK position as an example, the ignitionswitch 83 is energized into conduction so that the power supply controlterminal 73 is grounded. With the operation knob 85 in the ACC position,the ON position or the START position, the ignition switch 83 is openedso that the power supply control terminal 73 is not grounded. With thisarrangement, while the vehicle is running, the ACT-use power supply unit71 interrupts the power supply to the solenoid 7 and the motor driverelay 81. As a result, there is no possibility that the solenoid 7 andthe motor 3 may be operated due to a malfunction or the like, so thatthe possibility that the steering shaft 97 is mis-locked while thevehicle is running can be eliminated.

[0060] The control circuit section 70 includes the control unit 76 forcontrolling the operations of the solenoid 7 and the motor 3, and acommunication control unit 77 for receiving and analyzing a steeringunlocking signal and a Locking signal directed from external for acommunication terminal 78, and for transmitting a specified signal tothe control unit 76. The control unit 76 operates in connection with apower supply unit 74 connected to the battery terminal 72 and with a GNDterminal 79 which is to be grounded, and the control unit 76, to whichthe grounding-side terminal of the solenoid 7, the move detection switch66 and the motor drive relay 81 are connected, controls the operationsof the solenoid 7 and the motor 3 according to signals from thecommunication control unit 77 and the move detection switch 66.

[0061] Next, operation of the electrically-operated steering lock devicehaving the above constitution is described.

[0062] While the operation knob 85 is in the LOCK position, the steeringshaft 97 is locked, the ignition switch 83 is conducting, and the powersupply control terminal 73 of the ACT-use power supply unit 71 isgrounded. In this state, the solenoid 7 and the motor drive relay 81 arefed with electric power, thus being in an operable state. Further, inthis state, the control unit 76, upon receiving via the communicationcontrol unit 77 a locking signal derived from external, actuates themotor drive relay 81, so that an electric current is fed to the motor 3.

[0063] Then, with the electrically-operated steering lock device in thelock state shown in FIG. 3, when the electric current is fed to themotor 3 so that the motor 3 is driven, the final reduction gear 4, therotor 5 and the cam member 6 in which the engagement surface 50 isengaged with the unlocking-use engagement portion 45 of the rotor 5 arerotated together clockwise via the rotating mechanism 32.

[0064] As the cam member 6 is rotated clockwise, the first cam wallsurface 51 of the cam member 6 is brought into contact with the contactsurface 18 of the first lock bolt 1, so that the first lock bolt 1 ispressed toward the retreat direction, thus being rotated clockwise.Also, the coupling convex portion 29 of the second lock bolt 2protruding into the coupling-use elongate hole 17 of the first lock bolt1 is moved in engagement, so that the second lock bolt 2 is also pressedtoward the retreat direction so as to be rotated counterclockwise. Whenthis occurs, as shown in FIG. 4, the protruding pieces 16, 28 of thefirst and second lock bolts 1, 2 leave away from the receiving portion98 of the steering shaft 97 of the vehicle, by which the steering shaft97 is disengaged and unlocked.

[0065] In this case, the engagement piece 21 of the first lock bolt 1slides and moves while the locking member 62 keeps in contact with thetop surface of the engagement protruding portion 22 of the engagementpiece 21. When the first lock bolt 1 has moved to the retreat position,the contact between the engagement protruding portion 22 of theengagement piece 21 and the locking member 62 is released, and thelocking member 62 is moved toward the engagement piece 21 by the biasingforce of the spring 63, where the locking member 62 and the engagementprotruding portion 22 are engaged with each other. In this state, evenif the first lock bolt 1 tends to rotate in the protruding direction(counterclockwise), the first lock bolt 1 cannot rotate toward the lockside because the engagement protruding portion 22 of the engagementpiece 21 fixed to the first lock bolt 1 is engaged with the lockingmember 62.

[0066] Then, when the cam member 6 is rotated to the position shown inFIG. 4, the final reduction gear 4 comes into contact with the side wallof the accommodation recessed portion 11 b of the cover 11, blocking therotation of the cam member 6. After a specified time elapse, the motordrive relay 81 is operated so that power to the motor 3 is cut off.

[0067] Then, after the steering shaft 97 is unlocked as described above,the operation knob 85 is rotated to the START position via the ACCposition and the ON position, where the engine is started up, resultingin a running-ready state. In this state, the ignition switch 83 isopened and the power supply control terminal 73 of the ACT-use powersupply unit 71 is not grounded, so that the solenoid 7 and the motordrive relay 81 are not fed with electric power in this state so as to beinoperable, thus the motor 3 never being operated. As a result, thefirst and second lock bolts 1, 2 are held in the retreat position, thuseliminating the possibility that the steering shaft 97 is locked duringthe running of the vehicle.

[0068] Subsequently, when the operation knob 85 is operated to the LOCKposition with the vehicle stopped, the ignition switch 83 goes ON, thepower supply control terminal 73 of the ACT-use power supply unit 71goes grounded, and the solenoid 7 and the motor drive relay 81 are fedwith power so as to be operable. At this time point, the control unit76, receiving via the communication control unit 77 a locking signalderived from the external, makes the grounding-side terminal of thesolenoid 7 grounded to make the solenoid 7 operated. As the solenoid 7is operated so that the locking member 62 is moved toward the solenoid 7by the plunger 61, the engagement between the locking member 62 and theengagement protruding portion 22 of the engagement piece 21 is released.Then, upon detection of the operation of the solenoid 7 by the movedetection switch 66, the control unit 76 actuates the motor drive relay81 so that an electric current in the reverse direction to that of theunlocking signal is fed to the motor 3.

[0069] Then, while the electrically-operated steering lock device is inthe unlocked state shown in FIG. 4, an electric current is fed to themotor 3 so that the motor 3 is rotated reverse. Thus, the finalreduction gear 4, the rotor 5 and the cam member 6 with which thelocking-side engagement portion 44 of the rotor 5 is engaged through thespring 54 are rotated, via the rotating mechanism 32, counterclockwisetogether.

[0070] As the cam member 6 is rotated, the second cam wall surface 52 ofthe cam member 6 is brought into contact with the contact surface 18 ofthe first lock bolt 1, and the first lock bolt 1 is pressed in theprotruding direction so as to be rotated counterclockwise. Further, thecoupling convex portion 29 of the second lock bolt 2 protruding into thecoupling-use elongate hole 17 of the first lock bolt 1 is moved inengagement, the second lock bolt 2 is also pressed in the protrudingdirection so as to be rotated clockwise. In this operation, theprotruding pieces 16, 28 of the first and second lock bolts 1, 2 areprotruded outward from the through hole 11 a of the cover 11, enteringinto the receiving portion 98 of the steering shaft 97 of the vehicleand thereby being engaged with the receiving portion 98 of the steeringshaft 97, by which the steering shaft 97 is locked.

[0071] Then, as the cam member 6 is rotated to the position shown inFIG. 3, the final reduction gear 4 is brought into contact with the sidewall of the accommodation recessed portion 11 b of the cover 11, therebyinhibited from rotation, and after a specified time elapse, the powersupply to the motor 3 is cut off. Thereafter, the control unit 76 makesthe grounding-side terminal of the solenoid 7 opened, halting theconduction to the solenoid 7, where the locking member 62 comes intocontact with the top surface of the engagement protruding portion 22 ofthe engagement piece 21 by the biasing force of the spring 63.

[0072] In this state that the steering shaft 97 is locked, since theside wall of the cam member 6 is in contact with the first lock bolt 1,the first lock bolt 1 is held in the protrusion position. Therefore,even if an attempt to operate the first lock bolt 1 is made by magnet orthe like with an aim of theft, it is impossible to achieve theoperation. Further, even with an impact applied, since the first lockbolt 1 is never actuated, it is impossible to unlock the steering shaft97.

[0073] Furthermore, the contact position between the first lock bolt 1and the cam member 6 is set to such a position that when a force isapplied to the retreat position side of the first lock bolt 1, the forceis applied generally toward the rotational shaft of the cam member 6.Therefore, there occurs no rotational force to the cam member 6. Thus,the cam member 6 is not rotated, and so the first lock bolt 1 and thesecond lock bolt 2 interlocked with the first lock bolt 1 can be held inthe protrusion position with high reliability.

[0074] It is to be noted that, when the engine is stopped with thesteering shaft 97 kept rotated from the neutral position as shown inFIG. 5, it may occur, in some cases, that the protruding pieces 16, 28of the first and second lock bolts 1, 2 cannot be engaged with thereceiving portion 98 of the steering shaft 97. In this case, theprotruding pieces 16, 28 are in contact with the side surface of thesteering shaft 97 so as to be inhibited from moving, the cam member 6 isinhibited from rotating to the lock position (the position where thelock bolts 1, 2 are actuated to the protrusion position). However, sincethe spring 54 is provided between the locking-use engagement portion 44of the rotor 5 and the cam member 6, the rotor 5 is rotated, whilecompressing the spring 54, up to the lock position, and stopped there.Then, when the receiving portion 98 of the steering shaft 97 is rotatedup to the position corresponding to the protruding pieces 16, 28, theprotruding pieces 16, 28 become enterable into the receiving portion 98,so that the cam member 6 becomes rotatable. Thus, the cam member 6 isrotated counterclockwise by the biasing force of the compressed spring54, causing the first and second lock bolts 1, 2 to be rotated up to theprotrusion position, by which the steering shaft 97 is locked.

[0075] Further, when release of lock of the steering shaft 97 isattempted, a steering wheel torque may be applied thereto in some cases.For example, when a torque in a direction shown by an arrow A (clockwisedirection) is applied to the steering shaft 97 as shown in FIG. 6, notthat the slope surface 16 b of the first lock bolt 1 is brought intocontact with the receiving portion 98 of the steering shaft 97, but thatthe acceptance surface 28 a of the second lock bolt 2 is brought intocontact with the receiving portion 98, thus the acceptance surface 28 areceives the pressing force derived from the steering shaft 97 in adirection generally vertical to the acceptance surface 28 a. That is,the slope surface 16 b, which exerts a strong force in the rotationaldirection of the first lock bolt 1 when brought into contact with thereceiving portion 98, does not make contact with the receiving portion98. As a result of this, the force added by the steering wheel torqueonly causes a force to act along a direction generally vertical to therotational direction of the second lock bolt 2, and almost no rotationalforce toward the retreat side is applied to the second lock bolt 2. As aconsequence, the force with which the contact surface 18 of the firstlock bolt 1 presses the side face of the cam member 6 via the couplingconvex portion 29 can be reduced, so that the cam member 6 becomesrotatable with lighter force.

[0076] Further, when the cam member 6 is rotated clockwise, the secondlock bolt 2 is rotated in such a manner that the acceptance surface 28 agoes slightly away from the confronting surface of the receiving portion98. As a result, the degree of engagement between the acceptance surface28 a and the receiving portion 98 is weakened, making it easilyachievable to pull out the protruding piece 28 from the receivingportion 98.

[0077] Meanwhile, when a torque in a direction shown by an arrow B(counterclockwise direction) is applied to the steering shaft 97, notthat the slope surface 28 b of the second lock bolt 2 is brought intocontact with the receiving portion 98 of the steering shaft 97, but thatthe acceptance surface 16 a of the first lock bolt 1 is brought intocontact with the receiving portion 98, thus the acceptance surface 16 areceives the pressing force derived from the steering shaft 97 in adirection generally vertical to the acceptance surface 16 a. That is,the slope surface 28 b, which exerts a strong force in the rotationaldirection of the second lock bolt 2 when brought into contact with thereceiving portion 98, does not make contact with the receiving portion98. As a result of this, the force added by the steering wheel torqueonly causes a force to act along a direction generally vertical to therotational direction of the first lock bolt 1, and almost no rotationalforce toward the retreat side is applied to the first lock bolt 1. As aconsequence, the force with which the contact surface 18 of the firstlock bolt 1 presses the side face of the cam member 6 can be reduced, sothat the cam member 6 becomes rotatable with lighter force.

[0078] Further, as the cam member 6 is rotated clockwise, the first lockbolt 1 is rotated in such a manner that the acceptance surface 16 a goesslightly away from the confronting surface of the receiving portion 98.As a result, the degree of engagement between the acceptance surface 16a and the receiving portion 98 is weakened, making it easily achievableto pull out the protruding piece 16 from the receiving portion 98.

[0079] Although the present invention has been fully described by way ofexamples with reference to the accompanying drawings, it is to be notedthat various changes and modifications will be apparent to those skilledin the art. Therefore, unless otherwise such changes and modificationsdepart from the scope of the present invention, they should be construedas being included therein.

What is claimed is:
 1. An electrically-operated steering lock devicecomprising a lock bolt which is movable between a protrusion positionwhere a steering shaft is locked and a retreat position where thesteering shaft is unlocked, and actuating means for actuating the lockbolt from the protrusion position to the retreat position, wherein thelock bolt is composed of a first lock bolt which is pivotably held onone radial side in a neighborhood of the steering shaft and which has aprotruding piece to be engaged on its inner peripheral side with areceiving portion of the steering shaft, and a second lock bolt which ispivotably held on the other radial side in the neighborhood of thesteering shaft, which is rotatable to the protrusion position and theretreat position along with the first lock bolt and which has aprotruding piece to be engaged on its inner peripheral side with thereceiving portion of the steering shaft, and wherein the protrudingpieces of the two lock bolts are moved each in such a direction as to goaway from the engaging surface of the receiving portion of the steeringshaft when the engagement is released.
 2. The electrically-operatedsteering lock device according to claim 1, wherein each of theprotruding pieces of the two lock bolts has a slope surface provided onits outer peripheral side for avoiding interference with the receivingportion of the steering shaft.
 3. The electrically-operated steeringlock device according to claim 1, wherein the actuating means comprisesa cam member which has a first cam wall surface for making the firstlock bolt rotated from the protrusion position to the retreat positionand a second cam wall surface for making the first lock bolt rotatedfrom the retreat position to the protrusion position, and a couplingmeans for actuating the second lock bolt responsive to an actuation ofthe first lock bolt along therewith, and wherein the first lock bolt isheld at the protrusion position by the cam member.
 4. Theelectrically-operated steering lock device according to claim 3, whereineach of the protruding pieces of the two lock bolts has an acceptancesurface provided on its inner peripheral side for accepting torque ofthe steering shaft in a direction generally vertical to a rotationaldirection of each of the first and second lock bolts.
 5. Theelectrically-operated steering lock device according to claim 3, furthercomprising a spring for biasing the cam member in a direction toward alock position, and a rotor which has an engagement portion to be broughtinto contact with one end side of the spring to make the cam memberrotated toward the lock position via the spring and which is rotated bydrive of a motor to make the cam member rotated, wherein when the lockbolt is unable to be actuated to the protrusion position, the springabsorbs a move of the rotor and biases the cam member toward the lockposition.